Search results for "Phase"

Aluminum tri-isopropoxide as an alternative precursor for atomic layer deposition of aluminum oxide thin films

2019

Due to the safety challenges associated with the use of trimethylaluminum as a metal precursor for the deposition of alumina, different chemicals have been investigated over the years to replace it. The authors have investigated the use of aluminum tri-isopropoxide (TIPA) as an alternative alkoxide precursor for the safe and cost-effective deposition of alumina. In this work, TIPA is used as a stable Al source for atomic layer deposition (ALD) of Al2O3 when different oxidizing agents including water, oxygen plasma, water plasma, and ozone are employed. The authors have explored the deposition of Al2O3 using TIPA in ALD systems operating in vacuum and atmospheric pressure conditions. For the…

Low-temperature single crystal X-ray diffraction and high-pressure Raman studies on [(CH3)2NH2]2[SbCl5]

2007

The structure of bis(dimethylammonium) pentachloroantimonate(III), [(CH{sub 3}){sub 2}NH{sub 2}]{sub 2}[SbCl{sub 5}], BDP, was studied at 15 K and ambient pressure by single-crystal X-ray diffraction as well as at ambient temperature and high pressures up to 4.87(5) GPa by Raman spectroscopy. BDP crystallizes in the orthorhombic Pnma space group with a=8.4069(4), b=11.7973(7), c=14.8496(7) A, and Z=4; R{sub 1}=0.0381, wR{sub 2}=0.0764. The structure consists of distorted [SbCl{sub 6}]{sup 3-} octahedra forming zig-zag [{l_brace}SbCl{sub 5}{r_brace}{sub n}]{sup 2n-} chains that are cross-linked by dimethylammonium [(CH{sub 3}){sub 2}NH{sub 2}]{sup +} cations. The organic and inorganic substr…

The use of in-line quantitative analysis to follow polymer processing

2009

In this work it is presented three applications of real time analysis during extrusion process using an optical device developed by our research group, which applies the concepts of light extinction. Monitoring of polymer blends morphology takes place to infer data concerned to dispersed phase size and concentration. The detector also enables information about melting temperature of polymer during extrusion and the level of viscous heating, and the exfoliation step during processing of a polymer-clay nanocomposite.

CLOUD POINT MEASUREMENTS IN MEMBRANE FORMING SYSTEMS

2012

Temperature influence on the morphology of porous structures prepared via Thermally Induced Phase Separation (TIPS)

2013

A survey on models for the prediction of phase equilibria in polymer solutions

2011

New high-pressure phase and equation of state of Ce2Zr2O8

2012

In this paper we report a new high-pressure rhombohedral phase of Ce2Zr2O8 observed from high-pressure angle-dispersive x-ray diffraction and Raman spectroscopy studies up to nearly 12 GPa. The ambient-pressure cubic phase of Ce2Zr2O8 transforms to a rhombohedral structure beyond 5 GPa with a feeble distortion in the lattice. Pressure evolution of unit-cell volume showed a change in compressibility above 5 GPa. The unit-cell parameters of the high-pressure rhombohedral phase at 12.1 GPa are ah = 14.6791(3) {\AA}, ch = 17.9421(5) {\AA}, V = 3348.1(1) {\AA}3. The structure relation between the parent cubic (P2_13) and rhombohedral (P3_2) phases were obtained by group-subgroup relations. All t…

Productive Efficiency of Decanters with Short and Variable Dynamic Pressure Cones

2003

Abstract This paper presents the results of experimental trials carried out on third-generation, variable dynamic pressure cone decanters to assess machine performance and adjust the process parameters for optimum extraction yield. The results obtained led to the following conclusions: the regulation of the differential velocity screw/bowl allows a better performance of the decanter at low dilutions of the olive paste; it is possible to obtain high efficiency at a low dilution of the olive paste achieving a higher minor compounds content and the more advanced system of regulation leads to better results according to the variations of the ratio between liquid and solid phases, thus optimisin…

Theoretical and Empirical Description of Phases in the Proving Processes of Undergraduates

2018

International audience; In the presented study we adopt a process-oriented perspective on proving in order to gain further insights into relevant actions and typical obstacles in undergraduates' approaches to proving. The primary aim is to theoretically and empirically describe different phases, understood as bunches of intentionally closely related actions of proving. Therefore, we suggest a theoretical model of the proving process and confirm empirically that it can be used as an analytical tool for proving approaches. Based on this model, several proving processes have been analysed. In this paper we present first findings regarding the contribution of each phase to proof construction as…

Role of the support and pseudo-liquid phase in the Phosphotungstic Heteropolyacid (photo)catalytic activity

2016

Catalytic and photocatalytic tests for propene hydration to 2-propanol were successfully carried out by using binary materials obtained by supporting a Keggin or Wells-Dawson heteropolyacids via impregnation method to commercial SiO2 or TiO2. (Photo)catalytic hydration was studied in gas-solid regime by using a continuous (photo)reactor working at atmospheric pressure and 80 °C. The alcohol was the main product. The acidity of the cluster accounts for the catalytic role, whereas both the acidity of the cluster and the oxidant ability were responsible for the increase of the reaction rate of the photo-assisted catalytic reaction. Moreover, the presence of a photoactive semiconductor support …